1. Field of the Invention
The present invention relates generally to a method for creating a panoramic image, and more particularly, to a method for creating a panoramic image from multiple images obtained by photographing various portions of a subject that is smaller than, or falls within, a photographing range of a camera.
2. Description of the Related Art
A digital camera is a photographing device having an image sensor which converts an image of a subject that a user desires to photograph into electrical data and stores the electrical data. The photographing device is used for a variety of devices including a digital camera and a portable communication terminal. The digital camera can take a panoramic image, if it has a built-in program for creating a panoramic image, by converting an image of a subject into electrical data. Therefore, many recently developed digital cameras have been made to support various panoramic images.
The panoramic image refers to an image that has a higher aspect ratio than a normal aspect ratio of a camera, i.e., has a width much larger than its height. The panoramic image is used to photograph an object or target, such as landscape including a mountain and a sea, which is greater than a view angle of a camera, or to simultaneously express several sides of a moving or stationary target in one image.
The panoramic image may be composed using a plurality of continuously taken still images, or using multiple frames constituting a moving image. Separate panorama creation programs may be used to make a panoramic image using continuously taken images.
A method for creating a panoramic image includes assigning sequence numbers such as 1˜k, to continuously taken images of a predetermined size (w×h), extracting a region of a predetermined size (m×h; m<w) from the right side of a reference image (i.e., an i-th image, where 1≦i<k) to create an image R(i), extracting a region of a predetermined size (n×h; n<w) from the left side of the next image ((i+1)-th image) to create an image L(i+1), determining the same regions in the image R(i) and the image L(i+1), combining the i-th image with the (i+1)-th image on the basis of a portion found as the same regions, and repeatedly applying this process to a 1st image to a (k−1)-th image.
The above-described method for creating a panoramic image creates a panorama using still images, while a method for creating a panoramic image from a moving image continuously connects particular regions such as central potions of respective frames. This method includes assigning sequence numbers, such as 1˜k, to continuous frames of a predetermined size (w×h), extracting a region of a predetermined size (m×h; m<w) from the center of a reference frame(i.e., an i-th frame, where 1≦i<k) to create an image M(i), extracting a region of a predetermined size (m×h; m<w) from the center of the next frame ((i+1)-th frame) to create an image M(i+1), combining the image M(i) with the image M(i+1), and applying this process to a 1st frame to a (k−1)-th frame.
A conventional method for creating a panoramic image selects one image from among a plurality of taken images, compares the one image with another image located in front of or behind the one image to determine same regions, and synthesizes the images. This method is based on the assumption of continuously photographing images one by one by moving a camera. The above-described method of creating a panoramic image of the entire image by photographing the entire image is possible when creating a panoramic image for a target or subject greater than a camera's view angle, but may not be easily applied when creating a panoramic image for a target smaller than the camera's view angle. The method for creating a panoramic image from a moving image also has the same problem as the method for creating a panoramic image from still images.
That is, conventional panoramic image creation methods may not be easily applied to a subject smaller than a view angle of a photographing means.